1. Field of the Invention
The present invention relates to a communication apparatus, and more particularly to a communication apparatus configured to control a connection to a line network using a semiconductor DAA.
2. Description of the Related Art
Recently, there is a communication apparatus configured to control opening and closing of a phone line using a semiconductor data access arrangement (hereinafter may be referred to as an “SDAA”).
The line closing by the SDAA is performed by artificially making a terminal resistance by a voltage-and-current control of a transistor. In a conventional technique, a state of the line is measured by a line-state measuring portion integrated in the SDAA, and there are stored controlling conditions of line characteristics such as a voltage and a current judged by a value measured by the line-state measuring portion. This makes it possible to stabilize the line voltage and the line current supplied from an exchanger and to satisfactorily transmit and receive signals between the exchanger and the communication apparatus.